concanavalin-a and Atrophy

Chronic bowel disease can co-exist with severe autoimmune hepatitis (AIH) in an absence of primary sclerosing cholangitis. Genetic background may contribute to this overlap syndrome. We previously have shown that the deficiency of iPLA2β causes an accumulation of hepatocyte apoptosis, and renders susceptibility for acute liver injury. We here tested whether AIH induction in iPLA2β-null mice could result in intestinal injury, and whether bile acid metabolism was altered. Control wild-type (WT) and female iPLA2β-null (iPLA2β(-/-)) mice were intravenously injected with 10mg/kg concanavalinA (ConA) or saline for 24h. ConA treatment of iPLA2β(-/-) mice caused massive liver injury with increased liver enzymes, fibrosis, and necrosis. While not affecting WT mice, ConA treatment of iPLA2β(-/-) mice caused severe duodenal villous atrophy concomitant with increased apoptosis, cell proliferation, globlet cell hyperplasia, and endotoxin leakage into portal vein indicating a disruption of intestinal barrier. With the greater extent than in WT mice, ConA treatment of iPLA2β(-/-) mice increased jejunal expression of innate response cytokines CD14, TNF-α, IL-6, and SOCS3 as well as chemokines CCL2 and the CCL3 receptor CCR5. iPLA2β deficiency in response to ConA-induced AIH caused a significant decrease in hepatic and biliary bile acids, and this was associated with suppression of hepatic Cyp7A1, Ntcp and ABCB11/Bsep and upregulation of intestinal FXR/FGF15 mRNA expression. The suppression of hepatic Ntcp expression together with the loss of intestinal barrier could account for the observed bile acid leakage into peripheral blood. Thus, enteropathy may result from acute AIH in a susceptible host such as iPLA2β deficiency.

Topics: Animals; Apoptosis; Atrophy; Bile Acids and Salts; Chemical and Drug Induced Liver Injury; Concanavalin A; Duodenum; Female; Gastrointestinal Diseases; Genetic Predisposition to Disease; Goblet Cells; Group VI Phospholipases A2; Hepatitis, Autoimmune; Hyperplasia; Mice; Mice, Knockout; Permeability

Iron deficiency, a worldwide public health problem in children and adult women, impairs innate and cell-mediated immunity including interferon-γ secretion. Its effects on interleukin (IL)-4 have not been well investigated. Interleukin-4, a cytokine primarily secreted by TH2 lymphocytes, regulates B-cell proliferation and the switching of immunoglobulin (Ig)M to IgE subtypes; the latter is involved in the defense against helminth infection. Considering the fact that interferon-γ is a potent inhibitor of IL-4, we hypothesize that iron deficiency would increase the secretion of IL-4 and IgE. We measured IL-4 in serum and supernatant of concanavalin A and anti-CD3 antibody-treated spleen cells from iron-deficient, control, pair-fed DBA and C57BL/6 mice (20-24/group) and iron-replete mice for 3, 7, and 14 days (8-13/group). Feeding the low-iron diet (5 ppm vs 50 ppm for the control diet) for 2 months significantly reduced the mean levels of hemoglobin, hematocrit, liver iron stores, thymus weight, and induced splenomegaly in both strains of mice (P < .001). Iron deficiency, and not pair-feeding, reduced plasma IL-4 levels (P < .05), although it did not significantly affect IgE levels. Iron deficiency, especially when associated with thymus atrophy, reduced in vitro IL-4 secretion by activated spleen cells, cell proliferation, and percentage of CD4⁺IL-4⁺ cells (P < .05). Impaired cell proliferation did not fully explain reduced in vitro IL-4 secretion because iron-deficient mice with a normal thymus weight had a normal (3)H-thymidine uptake but decreased supernatant IL-4. It was likely due to low percentage of CD4⁺IL-4⁺. Iron repletion improved IL-4 measurements. Data suggest that iron deficiency has generalized negative effects on T-cell function. Unaltered plasma IgE may be due to other cytokines (ie, IL-13) that also modulate its secretion.

Topics: Anemia, Iron-Deficiency; Animals; Atrophy; CD3 Complex; CD4-Positive T-Lymphocytes; Cell Proliferation; Concanavalin A; Female; Hematocrit; Hemoglobins; Immunoglobulin E; Interferon-gamma; Interleukin-4; Iron; Iron Deficiencies; Iron, Dietary; Liver; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Organ Size; Spleen; Splenomegaly; Thymidine; Thymus Gland; Trace Elements

Herein we provide evidence that substance P (SP) and its neurokinin-1 receptor (NK-1R) expressed on thymocytes counteract thymus depletion induced by neonatal capsaicin (CPS) treatment by affecting thymocyte proliferation and apoptotic death. SP administration reversed the CPS-mediated inhibitory effects on the total thymocyte number and subset distribution, namely CD4+ and CD4- CD8- cells, through its interaction with NK-1R as shown by concomitant NK-1R (SR140333) antagonist administration. SP-induced enhancement of thymus cellularity parallels its ability of inhibiting the thymocyte apoptotic program. Indeed, exogenously administered SP completely nullified CPS-induced apoptosis, and SR140333 abrogated the SP-mediated protective effect. SP administration also stimulated concanavalin A (Con A)-induced thymocyte proliferation of CPS-treated rats, completely reversing the CPS-induced inhibition. The SP-mediated stimulation of Con A-induced thymocyte proliferation was NK-1R dependent as shown by concomitant administration of SP and SR140333 to CPS-treated rats. Our results also demonstrate that CPS treatment induces a marked decrease of thymocyte PPT-A mRNA level and endogenous SP content as evaluated by quantitative RT-PCR, in situ hybridization and cytofluorimetric analysis. By contrast, NK-1R mRNA levels were increased in thymocytes from CPS-treated rats. Exogenous SP administration augmented PPT-A, SP and NK-1R thymocyte expression in CPS-treated rats, and this enhancement was antagonized by SR140333 administration. Overall, our results strongly suggest that the immunomodulatory effects of neonatal CPS treatment on rat thymocyte functions are dependent on vanilloid-mediated regulation of SP and NK-1R functional expression by neuronal and immune cells.

Topics: Adjuvants, Immunologic; Animals; Animals, Newborn; Atrophy; Autocrine Communication; Binding Sites; Capsaicin; Cell Death; Cell Division; Concanavalin A; Growth Substances; Male; Neuroimmunomodulation; Neurokinin-1 Receptor Antagonists; Piperidines; Quinuclidines; Rats; Rats, Wistar; Receptors, Neurokinin-1; RNA, Messenger; Substance P; T-Lymphocytes; Thymus Gland; Up-Regulation

Elemental diets cause intestinal atrophy and reduced intestinal integrity, which can lead to significant increases in intestinal permeability and bacterial translocation. Recently, several lectins have been shown to have trophic effects on the intestine.. We examined the effects of concanavalin-A and phytohaemagglutinin on cell proliferation and crypt fission throughout the intestine of mice fed on elemental diets.. Mice were randomized to chow fed, elemental diet, elemental diet plus concanavalin-A and elemental diet plus phytohaemagglutinin groups. Cell proliferation and crypt fission were estimated in microdissected crypts. Plasma gastrin and enteroglucagon levels were measured by radioimmunoassay.. Elemental diet feeding significantly decreased cell proliferation and crypt fission of the middle and distal small intestine and throughout the colon. Phytohaemagglutinin significantly increased the weight of the intestine, but concanavalin-A had little effect. Cell proliferation in the small intestine was significantly increased by both lectins. However, in the stomach and colon, only phytohaemagglutinin increased proliferation. Crypt fission in the colon was dramatically increased by phytohaemagglutinin. Phytohaemagglutinin increased the plasma gastrin level, but not the enteroglucagon level.. Lectins have significant trophic effects on the small intestine and colon of mice fed elemental diets, and these actions vary between different sites in the gastrointestinal tract.

Topics: Animals; Atrophy; Cell Division; Colon; Concanavalin A; Food, Formulated; Gastric Mucosa; Gastrins; Intestine, Small; Lectins; Male; Metaphase; Mice; Organ Size; Phaseolus; Phytohemagglutinins; Plant Lectins; Radioimmunoassay; Random Allocation; Stomach; Weight Gain

Although the thymus is an important organ in the ontogeny of T lymphocytes, little is known about the effects of hemorrhage and/or trauma on this organ. The objective of this study was to determine whether trauma-hemorrhage induces increased thymic apoptosis and, if so, which mediators may be involved. Male C3H/HeN mice underwent either sham operation, hemorrhagic shock (mean artery blood pressure of 35 +/- 5 mmHg for 90 min, followed by blood and fluid resuscitation), fracture of the right tibia, or fracture plus hemorrhage, respectively. At 3 days after the procedure, total viable thymocyte yield, thymocyte apoptosis (flow cytometry), thymus-derived IL-3 (bioassay), and GM-CSF (ELISA) were determined. The results demonstrate that fracture alone induces no significant change in the parameters measured. However, (i) there was a significant decrease in total viable thymocyte yield and an increase in thymocyte apoptosis following hemorrhage or fracture plus hemorrhage; (ii) thymocyte IL-3 release was significantly reduced after hemorrhage as well as fracture plus hemorrhage; (iii) thymus-derived GM-CSF was significantly increased after fracture plus hemorrhage, but not with hemorrhage alone. In conclusion, severe hemorrhage alone or coupled with fracture can induce thymus atrophy via apoptosis. In addition, the decreased IL-3 release suggests that apoptotic thymic involution may be due to the lack of growth factor support. Such dyshomeostasis may contribute to inappropriate/inadequate T cell maturation leading to host immune suppression following trauma-hemorrhage. Increased thymus-derived GM-CSF might be in part responsible for the systemic inflammatory response following trauma-hemorrhage.

Topics: Animals; Apoptosis; Atrophy; Cell Count; Concanavalin A; DNA Damage; Enzyme-Linked Immunosorbent Assay; Flow Cytometry; Granulocyte-Macrophage Colony-Stimulating Factor; Interleukin-3; Male; Mice; Mice, Inbred C3H; Shock, Hemorrhagic; Thymus Gland; Tibial Fractures

The action of deltamethrin, a potent type II synthetic pyrethroid insecticide, on the thymus of the Balb/c mouse was studied in vivo and in vitro. We found that deltamethrin produced atrophy in the thymus in a dose- and time-dependent fashion. The lowest effective dose was found to be 6 mg/kg, 24 hr after a single intraperitoneal treatment. Treated animals did not recover during the time-course of the experiment (365 days after treatment); however, deltamethrin did not affect the body weight of the treated animals during the course of the study. To determine if deltamethrin-induced [Ca2+]i signaling could lead to thymic atrophy via programmed cell death, mice were treated with 25 mg deltamethrin/kg for 24 hr or the isolated thymocyte suspension was treated with 50 microM deltamethrin. A significant stimulation of inositol 1,4,5-triphosphate (IP3) and inositol 1,4-diphosphate (IP2) production was found after 24 hr of deltamethrin-1R (active isomer) treatment. An inactive stereoisomer of deltamethrin (i.e. 1S) did not cause a significant rise in the production of 1P3 and 1P2. In addition, deltamethrin-1R induced a transient increase of [Ca2+]i mobilization in the thymocyte suspension after 10 min of in vitro treatment, and substantially reduced the rate of calcium-calmodulin (Ca/CaM)-dependent protein dephosphorylation in in vivo treated animals (25 mg deltamethrin/kg for 24 hr). The in vivo effects of deltamethrin treatment demonstrated induction of DNA fragmentation and cell death in thymocytes. Moreover, using a histochemical approach, it was evident that deltamethrin at 25 mg/kg was able to produce cell death in the thymus of treated animals 72 hr after treatment. In the present work, we found that cell death was apoptotic in nature as noted first by the inhibition of deltamethrin-induced cell death by aurintricarboxylic acid, an inhibitor of apoptosis, and second, by internucleosomal DNA fragmentation, a hallmark of apoptosis, produced by deltamethrin in treated animals as well in thymocyte suspensions. In addition, the involvement of the Ca/CaM-dependent protein phosphorylation-dephosphorylation cascade in the induction of apoptosis by deltamethrin was supported by the protective role of the calmodulin inhibitor trifluoperazine against the apoptotic effect of deltamethrin on thymocyte suspension. Our results suggest that deltamethrin induced thymus atrophy and altered the Ca/CaM-dependent protein kinase-phosphatase cascade, which might induce programm

Topics: Animals; Apoptosis; Atrophy; Body Weight; Cell Survival; Cells, Cultured; Concanavalin A; Dose-Response Relationship, Drug; Injections, Intraperitoneal; Inositol 1,4,5-Trisphosphate; Inositol Phosphates; Insecticides; Kinetics; Male; Mice; Mice, Inbred BALB C; Nitriles; Pyrethrins; Signal Transduction; Stereoisomerism; T-Lymphocytes; Thymus Gland

Intestinal metaplasia of the stomach was grouped into 3 subtypes (A, B and C) according to the degree of pyloric gland involution which was judged from patterns of paradoxical Concanavalin A staining after Katsuyama and Spicer. The appearance of endocrine cells was investigated with immunohistochemical and silver methods. Type A metaplasia with slightly to moderately atrophic pyloric glands corresponded to the incomplete type in the previous classification, while Type C showing complete disappearance of pyloric glands corresponded to the complete type. Type B with severely atrophic pyloric glands was an intermediate. This subtyping reflects the cell kinetics in the intestinalized mucosa well. Regarding the endocrine cells, their total number varied in the order Type A greater than Type B greater than Type C. The selective populations of the endocrine cells including glicentin-containing cells, Grimelius-positive argyrophil cells without argentaffinity and intestinal-type enterochromaffin cells frequently formed hyperplastic foci in the intestinalized areas, where the other gut-type and proper gastric-type endocrine cells were scarcely noted. Immunoreactivity of glucagon or bovine pancreatic polypeptide were occasionally identified in a subpopulation of the glicentin-containing cells.

Topics: Adult; Aged; Atrophy; Concanavalin A; Enterochromaffin Cells; Gastric Mucosa; Glucagon; Histocytochemistry; Humans; Intestinal Mucosa; Metaplasia; Middle Aged; Pancreatic Polypeptide; Proglucagon; Protein Precursors; Pyloric Antrum; Staining and Labeling

Non-specific immunological modifications in mice during syngeneic gestation can be demonstrated. A dramatic transient thymic involution results from a significant reduction in the subpopulations of the thymic cortex with the remaining thymocytes being mainly medullary in nature. Response to PHA and Con A is greatly reduced in this pool which can normally be strongly stimulated. No suppressor cells or alteration in thymic epithelial function could be demonstrated. The unexpected low responsiveness of the remaining thymocytes was reversible after in vitro neuraminidase treatment. Meanwhile, MRL of thymocytes to allogeneic cell during syngenic gestation was not impaired.

Topics: Animals; Atrophy; Cells, Cultured; Concanavalin A; Female; Lymphocyte Activation; Lymphocyte Culture Test, Mixed; Mice; Mice, Inbred CBA; Mitosis; Neuraminidase; Phytohemagglutinins; Pregnancy; Pregnancy, Animal; T-Lymphocytes; Thymic Factor, Circulating; Thymus Gland

Quantitative analyses of electron micrographs have shown a decrease in the number of synapses in the dentate gyrus of the senescent Fischer-344 rat. The loss of synapses, involving both dendritic spines and shafts and axon terminals of more than one population of presynaptic neurons, did not depend upon the antecedent loss of postsynaptic neurons or their dendrites. These findings suggest that the age-related loss of synapses in the dentate gyrus may depend upon an inability of presynaptic elements to maintain the structural integrity of synapses in senescence. It is proposed that a change in the glycoprotein component of presynaptic plasma membranes resulting from a deficiency in axonal transport mechanisms in the septo-hippocampal pathway may underly this presynaptic malfunction. The resulting partial deafferentation of neurons in the dentate gyrus in senescence appears to be associated with a secondary atrophy of dendrites, which results in a loss of postsynaptic membranes before a loss of postsynaptic neurons can be documented.

Topics: Aging; Animals; Atrophy; Concanavalin A; Fucose; Glycoproteins; Hippocampus; Nerve Degeneration; Rats; Rats, Inbred F344; Septal Nuclei; Synapses